1. Field of the Invention
The present invention relates to a fuel tank.
2. Description of the Related Art
In a known fuel tank, the upper space in the interior of the fuel tank is connected to the fuel inlet pipe of the fuel tank via a breather pipe (for example, Japanese Unexamined Utility Model Publication No. 60-47627). In this fuel tank, when fuel is fed into the fuel tank from the fuel inlet pipe, and the level of the liquid surface of fuel in the fuel tank moves upward, the fuel vapor in the upper space of the fuel tank is discharged into the fuel inlet pipe via the breather pipe.
In this fuel tank, however, when fuel is fed into the fuel tank from the fuel pump nozzle, the fuel spouted from the nozzle comes into violent contact with and agitates the fuel in the fuel tank, causing bubbles to form in the fuel in the fuel tank. The collapsing of these bubbles causes a large amount of fuel vapor to be generated in the fuel tank, and this fuel vapor directly escapes from the fuel tank into the outside air via the fuel inlet pipe or escapes from the fuel tank into the outside air via the breather pipe and the fuel inlet pipe, causing air pollution.
In addition, the fuel inlet pipe is normally equipped with a sensor arranged on the outer circumferential face of the tip of the fuel pump nozzle to automatically stop the fuel feeding operation when the sensor comes into contact with the liquid fuel. Due to the presence of this sensor, when the level of the liquid surface of fuel in the fuel inlet pipe moves upward and reaches the level of the sensor, the fuel feeding operation is automatically stopped. However, this sensor reacts not only to the liquid fuel, but also to the fuel bubbles. Consequently, if a large amount of bubbles is generated as above-mentioned, a problem occurs in that, when the bubbles move upward in the fuel inlet pipe and come into contact with the sensor, the fuel feeding operation will be stopped although the level of the liquid surface of fuel in the fuel tank is low.